Molds for plastic materials



July 14, 1959 J. A. slNcLAlR 2,894,311

Moms FOR PLASTIC MATERIALS Filed Jan.\ 17, 1956 Z ik: l" y U M 1 f/ F1 if 1. if# if if i ,ma if i "ff 2f INVENTOR BY MMMM ATTORNEY United States Patent O MOLDS FORPDASTIC MATERIALS .lames A. Sinclair, Franklin, La. Application January 17, 1956, Serial No. 559,600

1 Claim. (Cl. 25--130) This invention relates .to molds designed primarily for use in the manufacture of concrete structures or receptacles such as septic tanks. More speciiically, this invention` concerns an improved concrete mold in which the` casting `can ,be` quickly and easily released from the coniningwalls of .the mold.

Generally speaking, casting methods and apparatus now` available, whether particularly adapted for casting structures from materials such as concrete, or whether adapted for. casting. from plastic material, have not satisfactorily vsolved. the problem of disengaging .the hardcned casting from the confining walls of the mold. In the past .in order to separate a heavy casting from the inner core of a mold it has beennecessary to laboriously turn the entire mold.`

`It is thus the principal object of the` present vinvention to` provide aA mold which effects the expeditious release ot'` the casting from the` conning structure without employment of the time consuming and laborious methods which` have been usedA in the past.

A `further objectof .the present invention is to provide a novel and advantageous relation of the outer and inner moldwall allowing the outer wall to lbe. removed Without` disturbing the inner wall.

A still `further object ot` the present invention is to provide a novel and advantageous relation ofthe outer wall` and casting supporting member permitting the removal ofthe `outer wall and release of the casting through movement of the supporting member.

Another object of the present invention is to provide a' moldcf simple, strong, durable and inexpensive con-` struction.

Other objects, features, and advantages will be apparent `from they, following description read in conjunction with the accompanying drawings in which` certain embodiments oi the. invention are illustrated -by way of examples.-

Inthe drawings,

Figure 1 is aplan view of a mold embodying the prin.- ciples ofthe invention;

lFigure 2 is a horizontal cross` section taken along the` lines Z-Z of Figure l;`

`Figure? is a fragmentary View, on an enlarged scale, showing the threaded pressure elements` disposed about the angle iron shown in Figure l;`

Figure 4` is a `fragmentary perspective View of` the flanged angle iron shown in Figure 3; and

Figure, 5 is a view similar toiliigure` 3 but a modication permitting the use of the same basic mold and sup porting structure forcasting receptacles of varying depths. Referring now -to the drawings in more detail, there is shown at I0 a frusto-conical core or inner form about which the concrete is poured. shape has been feund 4most useful in the manufacture of septic tanks. However, itwill be readily apparent that the shape and size of core may vary considerably. At 11 there is shown a conlining wall surrounding and spaced from core 10 when in assembled position. Wall 11 may, if

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desired, consist of a split jacket having ltwo o1' more sections which iit about core 10 and are appropriately attached at their adjacent edges. The area immediately above core 10 remains uncovered so that concrete may be poured between core or inner form 1l) and wall 11`to any desired level. The concrete disposed above `core 10 then :becomes the top or bottom of the tank section` thus formed. Guiding members or bushings are shown at 13 which. tit about aperture 14 in wall 11. Though two of these spout-like guiding members or projections and associated apertures are shown, it will be evident that more thantwo may be provided, if desired. Pins 15 are inserted through the members 13 and apertures 14 to abut inner core 10 when concrete is poured into the form. In this way, holes are formed in the casting into which suitable grapples may be inserted to lift the casting from the mold.

The inner core 10` rests on and is welded or otherwise secured to suitable supporting members` such as the channel irons generally indicated at 16 and 17. It will be readily appreciated from Figure 2 that these channel irons are crossed and project :beyond `the area of core 10` to provide support for annular angle iron 18.

The angle iron ring or annulus 18 is disposed about and embraces the inner core 10. As maybe seen most clearly in Figures 3, 4 and 5, the vertical portion 19 of the ring"18 iits about the core 10 while the horizontal` portion` 20 supports the casting 21 and at the same` time provides support for the outer wall 11.` The ring 18 may additionally be provided -with a plurality of horizontal lianges 22. Four horizontal flanges 22 have been found preferable though it will be evident that the nurnf ber may vary considerably Without departing from the spirit of the invention. In the drawings, angle iron- 18 is shown as aring, but the shape of angle iron 18 mayvary considerably, depending upon the contour vof the tank or receptacle desired, the only limitation being that it snugly fit about core 10 and not lbe iXedl'y secured` thereto. However, `it is most important that angle iron 18 be capable of vertical displacement along core 10.

FiXedly secured to outer wall 11 are a plurality of outwardly projecting [bracket members 2,3,.these bracket members being provided with horizontal,` anges having threaded apertures for the reception of set screws 25. Four Ibrackets and associated set screws have ybeen found preferable, though the invention is not limited to this number. The set screws 25 threaded through the apertures in bracket members 23 abut the horizontal ange 22 of angle iron 18. Thus, by tightening set screws Z5 in the apertures of bracket members 23 and nuts 24, the outer wall`11` of the mold to which these screws are operatively secured is forced upward, thus releasing casting `21 from` wall 11. In this way a very eiective means for forcing the outer wall 11 upward is provided. It will be readily appreciated, however, that` the present invention in its broadest aspects contemplates the employment of other lifting` means as well as the threaded pressure elements described.

Channel bars 16 and 17 are provided with a plurality of threaded apertures 26 which accommodate associatedI set screws 28. By screwing set screws 2'8`through` aper-` tures `26 against` angle iron 18 the casting is loosened` from its position against inner core 10` and may then` be easily removed from the core. Lock tuts 29 may :be provided on the screws 0r bolts 28 if desired. Hy-` draulic pressure or other lifting meansmay be used, if

desired, in lieu of threaded pressure elements thoughI the set screw assembly described is preferred. l

In operation, the present invention is keynoted by ease and facility of operation. Inner core or form 10 is welded or otherwise attached to the cross channel bars 16 and 17. The angle iron ring 18 is then placed about core and its horizontal portion 20 lies substantially parallel to the channel barupon which it rests. Angle iron 18 thus serves as a lloor for the mold andas a supporting member for the outer wall 11. The set screws 28 are placed in their lowermost vposition andmay beturned in their apertures 26, until 'they barely abut the under side of vthe angle iron 18. The outer wall 11 is then placed about the inner core, leaving space as is shown most clearly in Figure l for the reception of concrete or 'other suitable plastic material. This outer wall 11 may be secured in place by any suitable means. Thus, `the outer wall 11 may be secured in place by pins andI clamps. 11 may be provided with an outwardly extending horizont'al angle. Corresponding holes may then be drilled through'this angle andhorizontal ange 22 of angle iron 18 about the diameter ofythe'formrand tapered pins inserted to maintain the form in its proper position. .The

set screws 25 and associated nuts 24 are then' positioned in bracket 23 as shown. At this time, if desired, core pins' such 'as 1S may be inserted in the apertures 14. The casting material Ais now poured into the recess between'the' inner core 10 and the outer wall '11, over the'top of the form, struck oi level, and allowed to harden. Before complete hardening, pins may be removed. Set screws 25 are then turned so that outer wall 11 is urged upward and loosened from its posi- Vthe'ii'mer vcore '10 so that its' vertical portion 189 abuts i For example thebase of the outer wall conical castings such as shown in Figure 1v ofr the drawings, can be cemented together face-to-face, and with a maximum size half-receptacle the combined tank might have a capacity of 750 gallons to meet demands for a large size tank. For an approximate minimum requirement of 500 gallons, two smaller size half-tanks could be made according to the illustration in Figure 5 of the drawings; and if an intermediate size tank of, say, 600 gallons were required, one large size half-receptacle and one smaller size half-receptacle could be united to form the iinished tank. Of course, pipe inlet openings for the tanks can be provided by making suitable perforations .in the Walls 10 or 11 and inserting the necessary core forms.

It will, of course, be readily understood that, although the present invention has been described in great particularity with reference to the preferred embodiment shown in the accompanying drawings, the specific structure shown and described may be modified considerably with out departing from the spirit of the invention.y

Having thus described this invention, what is claimed as new and desired to be secured by Letters Patent is:

Mold apparatus for a hollow concrete casting such as an open-ended receptacle or the like, said apparatus tion surrounding casting'Zl.' The wall 11 may then be lifted oi. The set screws 28 may then `be similarly turned to urge rolled angle iron 18' upward, thus loosening'the casting so that it may be eas-ily removed from the mold. It has been found that tightening set screws 28 as little as IAG is sufficient to release the casting' from the core 10 even when bearing the weight of the outer wall of the mold. 'It is thus possible to completely free the casting Z1 from the inner core 10 and outer Wall 11 with a minimum of effort. The hardened casting may then be lifted through the use of the lift holes formed by pins 15.

When desired, a second angle ring 35 may be disposed at' any point along the height of the inner core 10, depending on the size of the tank required. Thus, when a smaller ring 35 is called for, a series of legs or elevating members 31 may be employed to hold the angle iron 35 at any height along core 10. This elevating member maybe placed upon angle iron 18 as shown in Figure 5.'A It will be immediately evident that outside form 11 rests on angle iron 18 even when a second angle iron 35 is employed. In this way it is possible to con' struct a casting which is smaller than'the innermold without the employment of a diterent core andouter Wall assembly. This aspect of the invention has found particular value .in the manufacture of septic tanks of dilerent sizes. By positioning a rolledY angle iron ring 35 at diierent levels about inner core 10, septic tank cores of different'dimensions and capacity'may .be constructed with relatively little additional expense since only an additional angle iron'of proper diameter is necessary. The present invention has, as a'consequence, the great advantage of being both economical and easily adapted to the manufacture of a great variety of concrete products of dil'erent shapes and sizes.

4 The above described method of'making variable sized shell-like receptacles or receptacleA parts tits in very well with the manufacture of septic tanks of'var'iable capacities. Boards of Health in certain municipalities sometimes have regulations requiring larger' septic tanks in some cases than in others and this method of manufacture provides exibility in meeting these demands, while using' much of the same basic form and supporting frame materials.- For example, two tub-like frustospaced radially outwardly from said coremember a distance equal to the wall thickness of the hollow casting desired, the lower edges of said outer wall member rest` ing upon said bottom plate' when the mold parts are in operative casting position; said bottom plate comprising an annulus of angle cross section having an outwardly extending horizontal ilange upon which the casting and theouter mold wall member rest, and a' radially inwardly disposed depending vertical ange which, in its lowermost position for casting, rests upon said support-V ing `trame; iirst screw-jack means threaded .through a portion of said supporting frame and disposed to Contact the bottom surface of said bottomY plate, exert upward' pressure thereon, and thus force the casting-supporting bottom plate and the core member apart vertically, the tapered configuration' of the core and casting serving'to accomplish the effective separation of those parts' through a -relatively shorty movement of said 'rst screwjack means; radially outwardly projecting brackets secured to the lower portionsv of said outer wall'member; second' References Cited in the le of this patentl UNITED STATES PATENTS Y 1,983,757 Hick Dec. 11, 1934- 2,250,020 Henderson July 22, 1941 2,486,038 Landon oet. 25, 1949` 2,510,810

Furst June v6, 1 950 

